Browsing NTNU Open by Author "Moan, Torgeir"
Now showing items 1-20 of 199
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A 5MW direct-drive generator for floating spar-buoy wind turbine: Drive-train dynamics
Sethuraman, Latha; Xing, Yihan; Venugopal, Vengatesan; Gao, Zhen; Mueller, Markus; Moan, Torgeir (Journal article; Peer reviewed, 2017)This article proceeds with investigations on a 5 MW direct-drive floating wind turbine system (FWTDD) that was developed in a previous study. A fully integrated land-based direct-drive wind turbine system (WTDD) was created ... -
A combined wind and wave energy-converter concept in survivalmode: Numerical and experimental study in regular waves with afocus on water entry and exit
Wan, Ling; Greco, Marilena; Lugni, Claudio; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Water entry (including slamming) and exit phenomena as well as green water on deck were observed during survivability model tests of a combined wind and wave energy converter concept. Here, a nonlinear numerical ... -
A comparative fatigue reliability study for key structural components of offshore wind turbines
Dong, Wenbin; Li, Qinyuan; Gao, Zhen; Moan, Torgeir (Chapter, 2018)In this paper, the fatigue reliability of blade root and tower base of a jacket wind turbine, the OC4 semi-submersible wind turbine and a land-based wind turbine is investigated and compared. The fatigue reliability of ... -
A comparative study of different methods for predicting the long-term extreme structural responses of the combined wind and wave energy concept semisubmersible wind energy and flap-type wave energy converter
Li, Qinyuan; Michailides, Constantine; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2018)The combined wind and wave concept semisubmersible wind energy and flap-type wave energy converter was developed in the EU FP7 project MARINA Platform. It consists of a four-column semisubmersible with a 5-MW wind turbine ... -
A comparative study on dynamic responses of spar-type floating horizontal and vertical axis wind turbines
Cheng, Zhengshun; Wang, Kai; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Interest in the exploitation of offshore wind resources using floating wind turbines has increased. Commercial development of floating horizontal axis wind turbines (FHAWTs) is emerging because of their commercial success ... -
A comparison of extreme structural responses and fatigue damage of semi-submersible type floating horizontal and vertical axis wind turbines
Cheng, Zhengshun; Madsen, Helge Aagard; Chai, Wei; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Currently development of floating wind turbines for deep water is mainly based on horizontal axis wind turbines (HAWTs). However, floating vertical axis wind turbines (VAWTs) are possible alternative due to their potential ... -
A comparison of two fully coupled codes for integrated dynamic analysis of floating vertical axis wind turbines
Koppenol, Boy; Cheng, Zhengshun; Gao, Zhen; Ferreira, Carlos Simão; Moan, Torgeir (Journal article; Peer reviewed, 2017)This paper presents a comparison of two state-of-the-art codes that are capable of modelling floating vertical axis wind turbines (VAWTs) in fully coupled time-domain simulations, being the HAWC2 by DTU and the SIMO-RIFLEX-AC ... -
A Comparison Study on the Hydroelasticity of Two Types of Floating Bridges in Inhomogeneous Wave Conditions
Li, Shuai; Fu, Shixiao; Wei, Wei; Moan, Torgeir (Chapter, 2018)Due to the interaction between elastic structural deformations and fluid motions, the responses of floating bridges should be analyzed by hydroelasticity methods. We firstly employed a linear time-domain approach, based ... -
A discrete-modules-based frequency domain hydroelasticity method for floating structures in inhomogeneous sea conditions
Wei, Wei; Fu, Shixiao; Moan, Torgeir; Lu, Ziqi; Deng, Shi (Journal article; Peer reviewed, 2017)Based on the three-dimensional (3D) potential theory and finite element method (FEM), this paper proposes a new numerical method for hydroelastic predictions of floating structures in inhomogeneous seabed and wave field ... -
A fully coupled method for numerical modeling and dynamic analysis of floating vertical axis wind turbines
Cheng, Zhengshun; Madsen, Helge A.; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2017)Offshore wind energy is one of the most promising renewable energy resources and an increasing interest arises to develop floating vertical axis wind turbines (VAWTs), which have the potential to reduce the cost of energy. ... -
A hybrid empirical-numerical method for hydroelastic analysis of a floater-and-net system
Ma, Leixin; Hu, Ke; Fu, Shixiao; Moan, Torgeir; Li, Runpei (Journal article, 2016)Because of scale effects and inappropriate hydrodynamic models, the nonlinear hydroelastic response of net cages used for fish farming cannot be analyzed precisely with traditional model testing or combinations of FEMs ... -
A prognostic method for fault detection in wind turbine drivetrains
Rasekhi Nejad, Amir; Odgaard, Peter Fogh; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2014)In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to ... -
A sensitivity study of wave and wind induced responses of the combined energy concept SFC based on experimental measurements
Michailides, Constantine; Gao, Zhen; Moan, Torgeir (Journal article, 2016)This paper deals with a sensitivity study of wave and wind induced responses of the combined energy concept SFC in operational and survival conditions. The sensitivity study is conducted based on experimental data. The ... -
A study on fully nonlinear wave load effects on floating wind turbine
Xu, Kun; Shao, Yanlin; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2019)The influence of fully nonlinear wave effects on floating wind turbine has been studied in this paper by comparing both floater motions and structural responses of tower base and mooring lines exposed to linear and fully ... -
A Systematic Design Approach of Gripper’s Hydraulic System Utilized in Offshore Wind Turbine Monopile Installation
Rasekhi Nejad, Amir; Li, Lin; Guachamin Acero, Wilson Ivan; Moan, Torgeir (Chapter, 2018)This paper presents a systematic approach for designing the hydraulic mechanism as a part of the gripper system employed in offshore wind turbine monopile installation. Traditionally, such equipments used in marine operation ... -
A Time-Domain Method for Hydroelastic Analysis of Floating Bridges in Inhomogeneous Waves
Fu, Shixiao; Wei, Wei; Ou, Shaowu; Moan, Torgeir; Deng, Shi; Lie, Halvor (Chapter; Peer reviewed, 2017)Based on the three dimensional potential theory and finite element method (FEM), this paper presented a method for time-domain hydroelastic analysis of a floating bridge in inhomogeneous waves. A floating bridge in both ... -
Aerodynamic Modeling of Offshore Vertical Axis Wind Turbines using the Actuator Cylinder Method
Cheng, Zhengshun; Madsen, Helge A.; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2016)Recently the interest in developing vertical axis wind turbines (VAWTs) for offshore application has been increasing. Among the aerodynamic models of VAWTs, double multi-streamtube (DMST) and actuator cylinder (AC) models ... -
An Integrated Dynamic Analysis Method for Simulating Installation of a Single Blade for Wind Turbines
Zhao, Yuna; Cheng, Zhengshun; Sandvik, Peter Christian; Gao, Zhen; Moan, Torgeir (Journal article; Peer reviewed, 2018)Installation of blades for wind turbines is challenging due to large lifting height and high precision. Assessment of blade dynamic responses during installation needs advanced simulation tools which are limited at present. ... -
An Overview of Analysis and Design of Offshore Wind Turbines
Moan, Torgeir; Bugalski, Thomas (Chapter, 2016)Offshore wind provides an important source of renewable energy and new opportunities for marine technology. Various fixed and floating concepts have been proposed for offshore wind application. Offshore wind turbines (OWTs) ... -
Analysis of Lifting Operation of a Monopile Considering Vessel Shielding Effects in Short-crested Waves
Li, Lin; Gao, Zhen; Moan, Torgeir (Journal article, 2016)This paper addresses numerical simulations of the lifting operation of an offshore wind turbine monopile foundation, considering both the shielding effects of the vessel and the spreading of the waves. A numerical model ...